Alkoxylated phosphite ester and process therefor

ABSTRACT

A composition and a process for producing the composition are disclosed. The composition comprises an alkoxylated phosphite ester which has the formula of (HO[{CH(R)} m O] n ) 3 P in which each R can be the same or different and can be independently hydrogen or an alkyl group, or combinations of two or more thereof and m is a number from 2 to about 20 and n is a number from 2 to about 20. The process comprises contacting a trialkyl phosphite with an alkylene glycol or polyalkylene glycol to produce a mixture followed by heating the mixture. Also disclosed in a process for using the composition, which comprises contacting a carbonyl compound, in the presence of the composition, with an alcohol.

FIELD OF INVENTION

This invention relates to a composition comprising an alkoxylatedphosphite ester, to a process for producing the ester, and to a processfor using the composition.

BACKGROUND OF THE INVENTION

Polyesters such as, for example, polyethylene terephthalate,polytrimethylene terephthalate and polybutylene terephthalate, are aclass of important industrial polymers. They are widely used inthermoplastic fibers, films, and molding applications.

Polyesters can be produced by transesterification of a dialkylterephthalate ester with a glycol followed by polycondensation or bydirect esterification of terephthalic acid with the selected glycolfollowed by polycondensation.

Organic titanates, such as tetraisopropyl and tetra n-butyl titanates,are known to be effective catalysts for producing polyester andfrequently are the catalyst of choice. However, these catalysts tend togenerate a significant amount of yellow discoloration when used aspolyesterification catalysts.

Therefore, there is an increasing need for developing a new compositionthat can be used as stabilizer for polyester and to reduce colorformation of polyester.

SUMMARY OF THE INVENTION

A composition comprises an alkoxylated phosphite ester (or polyalkyleneglycol phosphite ester) which has the formula of(HO[{CH(R)}_(m)O]_(n))₃P in which each R can be the same or differentand can be independently hydrogen, an alkyl group, or combinationsthereof, m is a number from 2 to about 20, n is a number from 1 to about20.

A process comprises contacting a phosphite ester with a glycol orpolyalkylene glycol under a condition effective to produce analkoxylated phosphite ester.

A process, which can be used for producing polyester, comprisescontacting a carbonyl compound, in the presence of the composition, withan alcohol to produce polyester.

Also provided is a process, which can be used for producing polyester.It comprises contacting a carbonyl compound, optionally in the presenceof a catalyst, with an alcohol to produce a product comprising anoligomer and contacting the product with an alkoxylated phosphite esterin which the catalyst can be any esterification or transesterificationor polycondensation catalyst.

DETAILED DESCRIPTION OF THE INVENTION

The composition of this invention can be substantially or completelysoluble or a stable solution in a solvent such as, for example, water,an alcohol, or combinations thereof. The term “substantially” means morethan trivial. However, a substantial portion of the composition can alsobe suspended or dispersed in the solvent. The term “stable solution”means a solution remains solution without substantial precipitation orsuspension or dispersion of a solute at room temperature (about 25° C.)for at least about 1 day, or 5 days, or even 10 days.

The composition is, or can comprise or consist essentially of or consistof an alkoxylated phosphite ester which has the formula of(HO[{CH(R)}_(m)O]_(n))₃P in which each R can be the same or differentand can be independently hydrogen, an alkyl group having 1 to 10 carbonatoms per group, or combinations thereof, m is a number from 2 to about20 or 2 to 10, n is a number from 1 to about 20 or 1 to about 10.

Examples of alkoxylated phosphite esters include, but are not limitedto, tri-(ethylene glycol) phosphite, tri-(propylene glycol) phosphite,tri(isopropylene glycol) phosphite, tri-(butylene glycol) phosphite,tri-(isobutylene glycol) phosphite, tri-(pentylene glycol) phosphite,tri-(hexylene glycol) phosphite, tri-(nonylene glycol) phosphite,tri-(diethylene glycol) phosphite, tri-(triethylene glycol) phosphite,tri-(polyethylene glycol) phosphite, tri-(polypropylene glycol)phosphite, tri-(polybutylene glycol) phosphite or combinations of two ormore thereof.

The composition can be produced by contacting a trialkylphosphite withan alkylene glycol or polyalkylene glycol under a condition effective toproduce a product comprising an alkoxylated phosphite.

A trialkylphosphite having the formula of (R′O)₃P where R′ is an alkylgroup which can be substituted with a second alkyl group or aryl group.Examples of trialkylphosphites include, but are not limited to,trimethyl phosphite, triethyl phosphite, tripropyl phosphite, tributylphosphite, triisobutyl phosphite, triamyl phosphite, trihexyl phosphite,trinonyl phosphite, or combinations of two or more thereof.

A glycol or polyalkylene glycol can have the formula(HO[{CH(R)}_(m)O]_(n)H in which R, m, and n are the same as thosedisclosed above (if a polyalkylene glycol, m and n are each at least 2).Examples of alkylene glycols include, but are not limited to, ethyleneglycol, propylene glycol, isopropylene glycol, 1,4-butylene glycol,1,5-pentylene glycol, 1,6-hexylene glycol, 1,8-ocytlene glycol,1,9-nonylene glycol, or combinations of two or more thereof. Examples ofpolyalkylene glycols include, but are not limited to diethylene glycol,triethylene glycol, polyethylene glycol, polypropylene glycol,polybutylene glycol, or combinations of two or more thereof.

The condition can include a temperature in the range of from about 30°C. to about 250° C., or about 50° C. to about 200° C., or about 75° C.to about 150° C. under a pressure that can accommodate the temperaturefor a period of time from about 0.01 to about 10, or 0.1 to about 5, or0.1 to about 3 hours. Contacting under such condition produces a productcomprising an alkoxylated phosphite.

The process can be carried out in the presence of a catalyst in anamount from about 0.0001 to about 5 weight % of trialkylphosphite. Thecatalyst can be any known catalyst for catalyzing the reaction of aphosphite and glycol. An example of catalyst is a tetraalkyl titanate,also referred to as titanium tetrahydrocarbyloxide. Examples of suitabletetraalkyl titanates include those having the general formula Ti(OR)₄where each R is individually selected from an alkyl, cycloalkyl,alkaryl, hydrocarbyl radical containing from 1 to about 30, preferably 2to about 18, and most preferably 2 to 12 carbon atoms per radical andeach R can be the same or different. Tetraalkyl titanates in which thehydrocarboxyl group contains from 2 to about 12 carbon atoms per radicalwhich is a linear or branched alkyl radical are relatively inexpensive,readily available, and effective in forming a solution. Suitabletetraalkyl titanates include, but are not limited to, titaniumtetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide,titanium tetra-n-butoxide, titanium tetrahexoxide, titanium tetra2-ethylhexoxide, titanium tetraoctoxide, and combinations of two or morethereof.

Suitable tetraalkyl titanates can be produced by any means known to oneskilled in the art such as, for example, disclosed in U.S. Pat. No.6,066,714, the entire disclosure of which is herein incorporated byreferences. Examples of commercially available tetraalkyl titanatesinclude, but are not limited to, TYZOR® TPT and TYZOR® TBT (tetraisopropyl titanate and tetra n-butyl titanate, respectively) availablefrom E. I. du Pont de Nemours and Company, Wilmington, Del., USA(DuPont).

Thereafter, the product comprising the alkoxylated phosphite can befurther process by any means known to one skilled in the art to purify,or to recover, or to isolate the alkoxylated phosphite. The meansinclude any known distillation techniques known to one skilled in theart such as, for example, a distillation under reduced pressure (vacuumdistillation). The distillation can be carried out under a conditionincluding a temperature in the range of from about 0° C. to about 250°C., or about 30° C. to about 200° C., or about 50° C. to about 150° C.under a pressure that can accommodate the temperature for a period oftime from about 0.01 to about 10, or 0.1 to about 5, or 0.1 to about 3hours.

The composition comprising the alkoxylated phosphite can also compriseor be produced from titanium or a titanium compound such as, forexample, an organic titanium compound. An example of organic titaniumcompound can be tetraalkyl titanate as disclosed above.

A tetraalkyl titanate can also be combined with a zirconium compound toproduce a mixture comprising a tetraalkyl titanate and a zirconiumtetrahydrocarbyloxide. Examples of zirconium compounds include, but arenot limited to, zirconium tetraethoxide, zirconium tetrapropoxide,zirconium tetraisopropoxide, zirconium tetra-n-butoxide, zirconiumtetrahexoxide, zirconium tetra 2-ethylhexoxide, zirconium tetraoctoxide,and combinations of two or more thereof. The molar ratio of Ti/Zr can bein the range of from about 0.001:1 to about 10:1.

The composition can further comprise a complexing agent can be one ormore hydroxycarboxylic acids, alkanolamines, and aminocarboxylic acids.For example, a complexing agent can be an α-hydroxycarboxylic acid,alkanolamine, or α-aminocarboxylic acid in which the hydrocarbyl groupor alkyl group has 1 to about 15, preferably 1 to 10 carbon atoms pergroup, and combinations of two or more thereof. Examples of suitablecomplexing agents include, but are not limited to, lactic acid, glycolicacid, citric acid, tartaric acid, malic acid, diethanolamine,triethanolamine, tetrahydroxyisopropylethylenediamine, glycine,bis-hydroxyethyl glycine, hydroxyethyl glycine, and combinations of twoor more thereof.

The titanium compound can also be a titanium chelate, which comprises oris produced from a tetraalkyl titanate and a complexing agent, both asdisclosed above. A titanium chelate can be produced by any methods wellknown to one skilled in the art or is commercially available. Example ofcommercially available titanium chelate include those available fromDuPont such as, for example, TYZOR®LA (titanium bis-ammonium lactate),TYZOR®AA (bis-acetylacetonate titanate), TYZOR®DC (bis-ethylacetoacetate titanate), TYZOR®TE (bis-triethanolamine titanate), orcombinations of two or more thereof.

The composition can further comprise a hypophosphorous acid or its salt,which has the formula of H₂POM in which M is hydrogen, ammonium ion, ametal ion, or combinations of two or more thereof and the phosphorusatom is bonded to two hydrogen atoms. The metal ion can be any metal ionsuch as an alkali metal ion. The hypophosphorous acid or its metal saltsuch as sodium hypophosphite can be commercially available as an aqueoussolution.

Examples of solvent is water or an alcohol having the formula of R¹(OH)_(p), an alkylene glycol that can include those disclosed above, apolyalkylene glycol or alkoxylated alcohol having the formula ofR¹O[CH₂CH(R¹)O]_(p)H, or combinations of two or more thereof in whicheach R¹ can be the same or different and is a hydrocarbyl radical having1 to about 10 carbon atoms per radical; R¹ can be an alkyl radical; Acan be an alkylene radical having 2 to about 10 carbon atoms permolecule; and each p can be the same or different and is independently anumber in the range of from 1 about to about 10. Examples of solventsinclude, but are not limited to, water, ethanol, propanol, isopropanol,butanol, ethylene glycol, propylene glycol, isopropylene glycol,butylene glycol, 1-methyl propylene glycol, pentylene glycol, diethyleneglycol, triethylene glycol, 2-ethyl hexanol, and combinations of two ormore thereof.

Alternatively, the solvent can be that which is formed on reaction ofthe tetraalkyltitanate with the complexing agent such as, for example,isopropyl alcohol from tetraisopropyltitanate or n-butyl alcohol fromtetra n-butyltitanate.

The molar ratio of the complexing agent to tetraalkyl titanate can beany effective ratio that can substantially prevent the precipitation ofthe titanium compound in the presence of a solvent. Generally, the ratiocan be in the range of from about 1:1 to about 10:1, or about 1:1 toabout 7:1, or 1:1 to 4:1. The molar ratio of hypophosphorous acid or itssalt to titanium compound (P:Ti) can be any ratio that, when thecomposition is used as catalyst to produce a polyester, can reduce theyellowness of the polyester such as, for example, in the range of fromabout 0.1:1 to about 10:1, or about 0.5:1 to about 7:1, or 1:1 to 4:1.The molar ratio of tris-phosphite or diphosphonite ester to titaniumcompound (P:Ti) can be any ratio that, when the composition is used ascatalyst to produce a polyester, can reduce the yellowness of thepolyester such as, for example, in the range of from about 0.1:1 toabout 50:1, or about 0.5:1 to about 20:1, or 1:1 to 10:1.

The composition can further comprise a co-catalyst such as aluminum,cobalt, zirconium (as disclosed above), zinc, or a compound comprisingone or more of these metals, and combinations of two or more thereof.For example, zinc acetate, zinc chloride, zinc nitrate, zinc sulfate,aluminum chloride, aluminum hydroxide, aluminum acetate, aluminumhydroxychloride, cobaltous acetate tetrahydrate, cobaltous nitrate,cobaltous chloride, cobalt acetylacetonate, cobalt napthenate, cobalthydroxide, cobalt salicyl salicylate, and combinations of two or morethereof can be uses as co-catalyst.

The catalyst composition can be produced by any means known to oneskilled in the art such as, for example, that disclosed in U.S. Pat. No.6,066,714 disclosed above.

A process that can be used in, for example, the production of an esteror polyester is provided. The process comprises contacting, in thepresence of a catalyst, a carbonyl compound with an alcohol. Thecatalyst can comprise or be produced from titanium or a titaniumcompound and an alkoxylated phosphite disclosed above.

Any carbonyl compound, which when combined with an alcohol, can producean ester or polyester can be used. Generally, such carbonyl compoundsinclude, but are not limited to, acids, esters, amides, acid anhydrides,acid halides, salts of carboxylic acid oligomers or polymers havingrepeat units derived from an acid, or combinations of two or morethereof. An example of acid is an organic acid such as a carboxylic acidor salt or ester thereof.

A preferred process for producing an ester or polyester comprises,consists essentially of, or consists of contacting a reaction mediumwith a composition disclosed above in the first embodiment of theinvention. The reaction medium can comprise, consist essentially of, orconsist of an alcohol and either (1) an organic acid, a salt thereof, anester thereof, or combinations thereof or (2) an oligomer having repeatunits derived from an organic acid or ester.

The organic acid or ester thereof can have the formula of R²COOR² inwhich each R² independently can be (1) hydrogen, (2) hydrocarboxylradical having a carboxylic acid group at the terminus, or (3)hydrocarbyl radical in which each radical has 1 to about 30, carbonatoms per radical which can be alkyl, alkenyl, aryl, alkaryl, aralkylradical, or combinations of two or more thereof, or (4) combinations oftwo or more thereof. For example, an organic acid can have the formulaof HO₂CA¹CO₂H in which A¹ is an alkylene group, an arylene group,alkenylene group, or combinations of two or more thereof. Each A¹ hasabout 2 to about 30, or about 3 to about 25, or about 4 to about 20, or4 to 15 carbon atoms per group. Examples of suitable organic acidsinclude, but are not limited to, terephthalic acid, isophthalic acid,napthalic acid, succinic acid, adipic acid, phthalic acid, glutaricacid, acrylic acid, oxalic acid, benzoic acid, maleic acid, propenoicacid, and combinations of two or more thereof. Examples of suitableesters include, but are not limited to, dimethyl adipate, dimethylphthalate, dimethyl terephthalate, methyl benzoate, dimethyl glutarate,and combinations of two or more thereof.

Examples of carboxylic acid metal salts or esters thereof includes a5-sulfo isophthalate metal salt and its ester having the formula of(R³O₂C)₂ArS(O)₂OM¹ in which each R³ can be the same or different and ishydrogen or an alkyl group containing 1 to about 6, or 2, carbon atoms.Ar is a phenylene group. M¹ can be an alkali metal ion such as sodium.An example of the ester is bis-glycolate ester of 5-sulfo isophthalatesodium salt.

Any alcohol that can esterify an acid to produce an ester or polyestercan be used in the present invention. Examples of suitable alcoholsinclude, but are not limited to, ethanol, propanol, isopropanol,butanol, ethylene glycol, propylene glycol, isopropylene glycol,butylene glycol, 1-methyl propylene glycol, pentylene glycol, diethyleneglycol, triethylene glycol, 2-ethyl hexanol, and combinations of two ormore thereof.

When the carbonyl compound includes a 5-sulfo isophthalate metal salt orits ester as disclosed above, the alcohol can be ethylene glycol,propylene glycol, isopropylene glycol, butylene glycol, 1-methylpropylene glycol, pentylene glycol, diethylene glycol, triethyleneglycol, 1,6-hexylene glycol, cyclohexyl-1,4-bismethanol, andcombinations of two or more thereof. The contacting of a5-sulfo-isophthalate metal salt or its ester with a glycol produces abis-glycolate ester of 5-sulfo isophthalate metal salt.

The contacting of the carbonyl compound and alcohol can be carried outby any suitable means. For example, the carbonyl compound and alcoholcan be combined before being contacted with the catalyst. For example,the catalyst can be dispersed in an alcohol by any suitable means suchas mechanical mixing or stirring to produce a dispersion followed bycombining the dispersion with (1) a carbonyl compound and (2) an alcoholunder a condition sufficient to effect the production of a ester orpolyester.

An oligomer can have a total of about 1 to about 100, or about 2 toabout 10 repeat units derived from a carbonyl compound and alcohol.

Any suitable condition to effect the production of an ester or polyestercan include a temperature in the range of from about 150° C. to about500° C., preferably about 200° C. to about 400° C., and most preferably250° C. to 300° C. under a pressure in the range of from about 0.001 toabout 1 atmosphere for a time period of from about 0.2 to about 20,preferably about 0.3 to about 15, and most preferably 0.5 to 10 hours.

The molar ratio of the alcohol to carbonyl compound can be any ratio solong as the ratio can effect the production of an ester or polyester.Generally the ratio can be in the range of from about 1:1 to about 10:1,or about 1:1 to about 5:1, or 1:1 to 4:1.

The catalyst, expressed as Ti, can be present in the range of about0.0001 to about 50,000, or about 0.001 to about 10,000, or 0.001 to 1000ppmw, parts per million by weight (ppmw) of the medium comprisingcarbonyl compound and alcohol. The co-catalyst disclosed above, if used,can also be present in the same range (expressed as Zr, Zn, Al, or Co).Other ingredients such as conventional esterification andtransesterification catalysts (e.g., manganese) and those enhancingcatalyst stability or performance may be introduced to the productionprocess concurrent with, or following, introduction of the compositiondisclosed herein.

Also disclosed is a process that can be used to reduce the formation ofcolor of polyester. The process can comprise contacting a carbonylcompound, optionally in the presence of a catalyst, with an alcohol toproduce an oligomer and contacting the oligomer with an alkoxylatedphosphite ester. The carbonyl compound, alcohol, oligomer, and analkoxylated phosphite ester can be the same as those disclose above. Anycatalysts known to catalyze esterification or transesterification orpolycondensation can be used in the process. Examples of such catalystinclude antimony, manganese, cobalt, titanium, zirconium, zinc, aluminumor combinations thereof. Generally, an alkoxylated phosphite ester canbe introduced to a polyester process after an oligomer is produced suchas during polycondensation stage. Because the production of oligomer andpolyester process are well known to one skilled in the art, thedescription of which is omitted herein for the interest of brevity.

The following Examples are provided to further illustrate the presentinvention and are not to be construed as to unduly limit the scope ofthe invention. All TYZOR® products were obtained from DuPont disclosedabove.

EXAMPLES Example 1

Tri-(ethylene glycol) phosphite solution (TEGP) was produced by adding25 g of tributyl phosphite to 225 g of ethylene glycol to produce amixture. Tyzor® TPT (1 g) was added as catalyst and the mixture washeated to 115° C. and held for 1 hour. A 30 mm Hg (4 kPa) vacuum wasapplied and 22.7 g of n-butanol was removed by vacuum distillation. Theresultant solution contained about 9.4% tri-(ethylene glycol) phosphiteand about 1.36% phosphorous (P). The TEGP solution thus prepared wasused to produce catalysts 2 and 3 shown in Table 1. TABLE 1¹ CatalystMetals or Elements No. Catalyst Composition (Weight Ratio) 1 56.7% Sbglycolate (.2028), Sb/Co/P 23.7% Co acetate (.0886), (230/42/19) and 10%H₃PO₄ (.301) 2 TYZOR ® LA (.061), Zn Ti/Zn/Co/P/TEGP-P acetate (.1334)in 5 g water, (10/80/50/26/25) Co acetate (.1055) in 5 g water, 10%H₃PO₄ (.412), and example 1 (1.5 g) 3 TYZOR ® LA (.061), Zn acetateTi/Zn/Co/TEGP-P (.1334) in 5 g water, (10/80/50/26/25) Co acetate(.1055) in 5 g water, 10% H₃PO₄ (.412), and example 1(1 g) 4 TYZOR ®LA(.061), Zn acetate Ti/Zn/Co/P (.1334) in 5 g water, Co acetate(10/80/55/26) (.1165) in 5 g water, and10% H₃PO₄ (.413)¹TYZOR ® LA is titanium bis-ammonium lactate; TEGP-P is ppm P in TEGP

Example 2

The catalyst solutions prepared in Example 1 were used in a 1-literresin kettle provided with a Jiffy Mixer agitator rotating at 40 rpm, athermocouple, condenser and nitrogen sweep. The catalyst, 115 g ethyleneglycol, and 400 g terephthalic acid oligomer (TPA oligomer, produced bythe process disclosed in U.S. Pat. No. 6,066,714, column 8, line 5-22,the disclosure of the US patent is incorporated herein by reference).The agitator was turned on and the temperature increased to 275° C. overa period of about 2.5 hours. The contents were polymerized by holdingunder agitation at 275° C. and a pressure of 120 mm Hg (16 kPa) for 20minutes, and at 280° C. and a pressure of 30 mm Hg (4 kPa) for anadditional 20 minutes. The contents were then held under agitation at285° C. at 1 to 2 mm Hg (0.27 kPa) pressure for a time sufficient toreach 15 ounce-inch (0.106 Newton-meter) torque as measured by anElectro-Craft Motomatic torque controller. The time for this step wasrecorded as the Finish Time, and varied with the catalyst used. Thepolymer melt was then poured into a water bath to solidify the melt, andthe resultant solid annealed at 150° C. for 12 hours and ground to passthrough a 2 mm filter for color measurements using the previouslydescribed spectrophotometer. Results comparing the color as measuredspectrophotometrically are given in Table 2 below.

Color of the resulting polymer was measured in terms of the L-value andb-value, and a-value using an instrument such as SP-78Spectrophotometer. The L-value shows brightness, with the greater thenumerical value showing higher (desirable) brightness. A value of 78 ormore would be considered good. The b-value shows the degree ofyellowness, with a higher numerical value showing a higher (undesirable)degree of yellowness. Generally a b value below 7 can be consideredgood. The a-value represents degree of redness, a higher positivea-value is redder, lower negative is greener.

Table 2 shows that polyester product produced using the phosphitestabilizer (using catalysts 2 and 3) had consistently lower b-value thanthose using phosphoric acid (catalysts 1 and 4) as color stabilizer.TABLE 2 Catalyst Polycondensation Time No. (min) L-Value a-Value b-Value1 75 73.79 −1.74 5.03 2 135 81.63 −0.89 1.87 3 60 79.21 −1.31 2.16 4 3576.48 −1.1 6.53

1-27. (canceled)
 28. A process comprising contacting, in the presence ofa composition comprising an alkoxylated phosphite and an organictitanium compound, a carbonyl compound with an alcohol wherein saidalkoxylated phosphite has the formula of (HO[{CH(R)}_(m)O]_(n))₃Pwherein each R is independently hydrogen, an alkyl group, orcombinations of two or more thereof; m is a number from 2 to about 20;and n is a number from 1 to about
 20. 29. A process according to claim28 wherein said composition is tri-(ethyleneglycol) phosphite,tri(propylene glycol) phosphite; tri(isopropylene glycol) phosphite;tri(1,4-butylene glycol) phosphite; tri (-isobutylene glycol) phosphite;tri(pentylene glycol) phosphite; tri(hexylene glycol) phosphite;tri(octylene glycol) phosphite, tri(nonylene glycol) phosphite, tri(diethylene glycol) phosphite, tri(triethylene glycol) phosphite,tri(polyethylene glycol)phosphite, tri(polypropylene glycol) phosphite,tri(polybutylene glycol) phosphite; or combinations of two or morethereof.
 30. A process according to claim 29 wherein said composition istri-(ethylene glycol) phosphite.
 31. (canceled)
 32. A process accordingto claim 30 wherein said composition further comprising a complexingagent, which is a hydroxycarboxylic acid, an alkanolamine, anaminocarboxylic acid, or combinations of two or more thereof.
 33. Aprocess according to claim 32 wherein said composition furthercomprising a hypophosphorous acid, its salt, or both.
 34. A processaccording to claim 32 wherein said titanium compound is tetra isopropyltitanate, tetra n-butyl titanate, or combinations thereof.
 35. A processaccording to claim 33 wherein said titanium compound is tetra isopropyltitanate, tetra n-butyl titanate, or combinations thereof.
 36. A processaccording to claim 32 wherein said titanium compound is a titaniumchelate comprising or produced from a tetraalkyl titanate and saidcomplexing agent.
 37. (canceled)
 38. A process according to claim 36wherein said composition further comprises sodium hypophosphite.
 39. Aprocess according to claim 36 wherein said titanium or a titaniumcompound is titanium bis-ammonium lactate.
 40. A process according toclaim 39 wherein said composition is tri-(ethylene glycol) phosphite.